The technical field of the invention is that of the devices used in the field of automotive safety to protect a pedestrian in the event of a frontal impact between the said pedestrian and a motor vehicle.
When a pedestrian is struck by the front end of a motor vehicle, the pedestrian's head often comes into direct contact with the bonnet of the vehicle. The impact of the head on the bonnet causes the bonnet to deform. This deformation often occurs to such a point that the bonnet comes into contact with the engine block and any rigid parts such as suspension leg turrets, windscreen wiper mechanisms, etc. The movement of the pedestrian's head is then abruptly halted by the bonnet coming into contact with the engine block and therefore experiences a violent deceleration which may cause the pedestrian serious injury.
Prior art discloses documents which, in the event of an impact between a pedestrian and a motor vehicle, allow the vehicle bonnet to be raised by a certain amount so as to prevent the pedestrian's limbs and especially his head from being stopped, in the impact against the bonnet, by the engine block situated just under the bonnet. In the devices of the prior art, the raising of the bonnet is performed at the rear end of the bonnet, that is to say at the windscreen end, which is the opposite end to the end used for opening or closing the bonnet in normal operation, the bonnet remaining fixed at the front end of the motor vehicle.
Patent FR 2 848 947 relates to a safety device for raising the bonnet of a motor vehicle in the event of a collision, this device being situated under the said bonnet and comprising a mechanism for raising the said bonnet and an actuator, the said bonnet comprising a structure which, in normal operation, allows it to be opened or closed about an axis known as the pivot axis.
The main characteristic of this device is that the raising mechanism first of all undergoes an unlocking phase by performing a first, translational, movement.
The main characteristic of this device is that it undergoes an unlocking phase through a translational movement, followed by a deployment phase in a rotational movement. The safety device also foresees a later, shock-absorbing, phase allowing the bonnet to move with the struck pedestrian so as to lessen the effect of the said impact. However, no way of embodying such a shock-absorbing device is described. The safety devices according to the invention exhibit shock-absorbing devices the qualities of which are tailored to the requirements associated with the tight confines of motor vehicles and their low cost, namely, small size, simplicity of design and great reliability. Simplicity of design means that the shock-absorbing devices have not to require the addition of parts that need complex and costly machining.